The Surprising Root Cause of Anxiety and Depression

Most people would not automatically think about their gut when they think about brain health… but this is actually a perfect place to look, one that may very well hold the secret to improving your mood and mental health.

Does Your Gut Hold the Key to Better Brain Health?

You may not be aware that you actually have two nervous systems:

Central nervous system, composed of your brain and spinal cord

Enteric nervous system, which is the intrinsic nervous system of your gastrointestinal tract

Both are actually created out of the same type of tissue.

These two systems are connected via the vagus nerve.

The vagus nerve is the primary route your gut bacteria use to transmit information to your brain.

To put this into more concrete terms, you’ve probably experienced the visceral sensation of butterflies in your stomach when you’re nervous, or had an upset stomach when you were very angry or stressed. The flip side is also true, in that problems in your gut can directly impact your mental health, leading to issues like anxiety and depression.

For instance, in December 2011 the Journal of Neurogastroenterology and Motility reported the novel finding that the probiotic (good bacteria) known as Bifidobacterium longum NCC3001 has been shown to help normalize anxiety-like behavior in mice with infectious colitis.

As B. longum decreases excitability of enteric neurons, it may signal to the central nervous system by activating vagal pathways at the level of the enteric nervous system.

Separate research also found the probiotic Lactobacillus rhamnosus had a marked effect on GABA [an inhibitory neurotransmitter that is significantly involved in regulating many physiological and psychological processes] levels in certain brain regions and lowered the stress-induced hormone corticosterone, resulting in reduced anxiety- and depression-related behaviour.

When researchers severed the vagus nerve, GABA receptor levels and the animals’ behavior remained unchanged after treatment with L. rhamnosus, confirming that the vagus nerve is most likely the primary pathway of communication between the bacteria in your gut and your brain.

Interestingly, just as you have neurons in your brain, you also have neurons in your gut — including neurons that produce neurotransmitters like serotonin, which is also found in your brain. In fact, the greatest concentration of serotonin, which is involved in mood control, depression and aggression, is found in your intestines, not your brain! (Perhaps this is one reason why antidepressants, which raise serotonin levels in your brain, are often ineffective in treating depression, whereas proper dietary changes often help.)